Bytecode / conditional forecast: another fix test over consistency of variable flipping

The method Evaluate::getCurrentBlockEndogenous() would always return an empty
vector, because of a weirdness in FBEGINBLOCK class (after deserialization, the
latter has “variables” member unset and the corresponding data is instead store
in “Block_Contain_”).

On the master branch, the problem has been solved differently (the weirdness in
the FBEGINBLOCK class has been removed).

mex/sources/bytecode/Evaluate.hh

@@ -145,7 +145,10 @@ public:
   [[nodiscard]] auto
   getCurrentBlockEndogenous() const
   {
-    return currentBlockTag()->get_endogenous();
+    vector<int> endos;
+    for (auto& [eq, var, deriv] : getCurrentBlockEquationsAndVariables())
+      endos.push_back(var);
+    return endos;
   }
   [[nodiscard]] auto
   getCurrentBlockNbColJacob() const